Chicago (CNN) -- Doctors who treat breast cancer patients are very excited about an experimental drug that presents a whole new way of knocking out cancer cells. The drug, trastuzumab emtansine, commonly referred to as T-DM1, appears to be superior to the standard treatment for women with advanced HER2-positive breast cancer. Researchers are presenting the results of a large three-year clinical trial Sunday at the 2012 American Society of Clinical Oncology conference in Chicago. It's a combination of the targeted drug trastuzumab (the "T" in T-DM1), better known by the brand name Herceptin, and a very powerful chemotherapy drug called emtansine (the "DM1" part). The drug is designed to work when Herceptin alone no longer can keep the cancer in check.

So the Herceptin part of T-DM1 homes in on the cancer cells (sparing other healthy cells) and delivers the powerful

OPTIONS:
- American Society of Clinical Oncology chemo drug into the cell.
- CNN chemo drug into the cell.
- Chicago chemo drug into the cell.
- DM1 chemo drug into the cell.
- HER2 chemo drug into the cell.
- Herceptin chemo drug into the cell.
- T-DM1 chemo drug into the cell.


DM1 chemo drug into the cell.